一直在思考如果Server端用C，client用Java來實現，如何實現兩者之間的安全通信。其實這個比較成熟了，c語言推薦使用gnutls(考慮license問題)，Java使用 JSSE就可以解決這個問題。以下是示例代碼:
C Server 代碼：echoserver.c
/* This example code is placed in the public domain. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#define KEYFILE "collectd.csmtg.ericsson.com.key"
#define CERTFILE "collectd.csmtg.ericsson.com.cert"
#define CAFILE "ca.ericsson.com.cert"
#define CRLFILE "ca.ericsson.com.crl"
/* This is a sample TLS 1.0 echo server, using X.509 authentication.
*/
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */
/* These are global */
gnutls_certificate_credentials_t x509_cred;
gnutls_priority_t priority_cache;
static gnutls_session_t
initialize_tls_session (void)
{
gnutls_session_t session;
gnutls_init (&session, GNUTLS_SERVER);
gnutls_priority_set (session, priority_cache);
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, x509_cred);
/* We don't request any certificate from the client.
* If we did we would need to verify it.
*/
gnutls_certificate_server_set_request (session, GNUTLS_CERT_IGNORE);
return session;
}
static gnutls_dh_params_t dh_params;
static int
generate_dh_params (void)
{
int bits = gnutls_sec_param_to_pk_bits (GNUTLS_PK_DH, GNUTLS_SEC_PARAM_LOW);
/* Generate Diffie-Hellman parameters - for use with DHE
* kx algorithms. When short bit length is used, it might
* be wise to regenerate parameters often.
*/
gnutls_dh_params_init (&dh_params);
gnutls_dh_params_generate2 (dh_params, bits);
return 0;
}
int
main (void)
{
int listen_sd;
int sd, ret;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
socklen_t client_len;
char topbuf[512];
gnutls_session_t session;
char buffer[MAX_BUF + 1];
int optval = 1;
/* this must be called once in the program
*/
gnutls_global_init ();
gnutls_certificate_allocate_credentials (&x509_cred);
/* gnutls_certificate_set_x509_system_trust(xcred); */
gnutls_certificate_set_x509_trust_file (x509_cred, CAFILE,
GNUTLS_X509_FMT_PEM);
gnutls_certificate_set_x509_crl_file (x509_cred, CRLFILE,
GNUTLS_X509_FMT_PEM);
ret = gnutls_certificate_set_x509_key_file (x509_cred, CERTFILE, KEYFILE,
GNUTLS_X509_FMT_PEM);
if (ret < 0)
{
printf("No certificate or key were found\n");
exit(1);
}
generate_dh_params ();
gnutls_priority_init (&priority_cache, "PERFORMANCE:%SERVER_PRECEDENCE", NULL);
gnutls_certificate_set_dh_params (x509_cred, dh_params);
/* Socket operations
*/
listen_sd = socket (AF_INET, SOCK_STREAM, 0);
memset (&sa_serv, '\0', sizeof (sa_serv));
sa_serv.sin_family = AF_INET;
sa_serv.sin_addr.s_addr = INADDR_ANY;
sa_serv.sin_port = htons (PORT); /* Server Port number */
setsockopt (listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *) &optval,
sizeof (int));
bind (listen_sd, (struct sockaddr *) & sa_serv, sizeof (sa_serv));
listen (listen_sd, 1024);
printf ("Server ready. Listening to port '%d'.\n\n", PORT);
client_len = sizeof (sa_cli);
for (;;)
{
session = initialize_tls_session ();
sd = accept (listen_sd, (struct sockaddr *) & sa_cli, &client_len);
printf ("- connection from %s, port %d\n",
inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
sizeof (topbuf)), ntohs (sa_cli.sin_port));
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
do
{
ret = gnutls_handshake (session);
}
while (ret < 0 && gnutls_error_is_fatal (ret) == 0);
if (ret < 0)
{
close (sd);
gnutls_deinit (session);
fprintf (stderr, "*** Handshake has failed (%s)\n\n",
gnutls_strerror (ret));
continue;
}
printf ("- Handshake was completed\n");
/* see the Getting peer's information example */
/* print_info(session); */
for (;;)
{
memset (buffer, 0, MAX_BUF + 1);
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("\n- Peer has closed the GnuTLS connection\n");
break;
}
else if (ret < 0)
{
fprintf (stderr, "\n*** Received corrupted "
"data(%d). Closing the connection.\n\n", ret);
break;
}
else if (ret > 0)
{
/* echo data back to the client
*/
printf("Server receives a packet with content:%s\n", buffer);
gnutls_record_send (session, buffer, strlen (buffer));
}
}
printf ("\n");
/* do not wait for the peer to close the connection.
*/
gnutls_bye (session, GNUTLS_SHUT_WR);
close (sd);
gnutls_deinit (session);
}
close (listen_sd);
gnutls_certificate_free_credentials (x509_cred);
gnutls_priority_deinit (priority_cache);
gnutls_global_deinit ();
return 0;
}
GnuTLS 的詳細介紹：請點這裡
GnuTLS 的下載地址：請點這裡
